London has been battered by 50mph winds that have felled trees and caused travel chaos. Powerful gusts swept across the capital as the Met Office issued a yellow "be aware" weather alert for most of the country.

Boris Johnson insisted today that he could “open doors” for London businesses in India even though he has no powers over visas, taxes or aviation.

On the final day of his week-long tour — which has taken in Delhi, Hyderabad and Mumbai — the Mayor came under pressure to justify his trip.

He claimed the visit was already bearing fruit as he had made the personal contacts needed to “sell” the capital.

Mr Johnson has made 15 speeches and six visits, held four political meetings and attended five private business engagements over the past few days, taking in technology firms, airport operators, universities and banks.

But his trip has been dominated by questions over the UK’s complicated visa system, business regulation, taxes and aviation capacity — none of which are under the Mayor’s direct control.

At the Gate of India in Mumbai, he told reporters: “I’m not certain it’s true to say you can’t influence those decisions.

"If you look at what’s happening on aviation, the campaign run from City Hall over the last few years has led to an acceptance by government that they’ve got to increase capacity.

“The reason we’re all here is because the businesspeople repeatedly say they need the access that is given by a trip like this.

"Politicians, I’m afraid, are very useful in that they open doors, they get people talking to one another.”

The Mayor insisted he had found a “great deal” of enthusiasm among businesses for investing in London, though the hall was half empty for his speech to the Bombay Stock Exchange today.

He said he could help lift Indians out of poverty by helping open doors to free trade and investment.

Mr Johnson was quizzed over his future plans now that he has made his first big entry onto the international stage. He said he had made a “100 per cent binding resolution” to see out the end of his four-year term at City Hall.

However, he repeatedly refused to rule out becoming an MP — a prerequisite for a shot at the Tory leadership — at the same time.

He suggested the Chancellor should reduce the top rate of tax in next week’s Autumn Statement to bring it into line with India’s 30 per cent rate, adding it was “a point George Osborne might brood on”.

The Mayor defended his decision to litter his speeches with the same jokes. “I think some of those jokes have been done more than 12 times.

"That’s nothing in the life of a joke,” he quipped. He appeared on an Indian chat show this afternoon to round off his trip.

Labour’s leader in London, Len Duvall, said: “After strongly attacking Ken Livingstone for visiting India and setting up trade offices, it looks like Boris has finally realised that we do need a closer relationship with India.

“It’s a real shame the Mayor shut London’s trade offices in India when he first got elected and has wasted the years since.

"Let’s hope this is the start of a concerted effort by Boris to increase investment and isn’t just an attempt to make him look like a prime minister in waiting.”